Bug with `[<-.POSIXlt` on specific OSes

I?think?'[.POSIXlt'?and?'[<-.POSIXlt'?don't?need?to?normalize?out-of-range?values.?I?think?they?just?make?same?length?for?all?components,?to?ensure?correct?extraction?or?replacement?for?arbitrary?index.

I?have?a?thought?of?adding?an?optional?argument?for?'as.POSIXlt'?applied?to?"POSIXlt"?object.?Possible?name:
normalize
adjust
fixup

To?allow?recycling?only?without?changing?content,?instead?of?TRUE?or?FALSE,?maybe?choice,?like
fixup?=?c("none",?"balance",?"normalize")
,?where?"normalize"?implies?"balance",?or
adjust?=?c("none",?"length",?"content",?"value")
,?where?"content"?and?"value"?are?synonymous.

By?the?way,?Inf?in?'sec'?component?is?out-of-range!


For?'gmtoff',?NA?or?0?should?be?put?for?unknown.?A?known?'gmtoff'?may?be?[ositive,?negative,?or?zero.?The?documentation?says
?gmtoff? (Optional.) The offset in seconds from GMT: positive
values are East of the meridian.  Usually ?NA? if unknown,
but ?0? could mean unknown.


dlt?<-?.POSIXlt(list(sec?=?c(-999,?10000?+?c(1:10,-Inf,?NA))?+?pi,
????????????????????????????????????????#?"out?of?range",?non-finite,?fractions
?????????????????????min?=?45L,?hour?=?c(21L,?3L,?NA,?4L),
?????????????????????mday?=?6L,?mon??=?c(11L,?NA,?3L),
?????????????????????year?=?116L,?wday?=?2L,?yday?=?340L,?isdst?=?1L))

as.POSIXct(dlt)[1]?is?NA?on?Linux?with?timezone?without?DST.?For?example,?after
Sys.setenv(TZ?=?"EST")


----------------

?Martin?Maechler
?????on?Wed,?12?Oct?2022?10:17:28?+0200?writes:

?Kurt?Hornik
?????on?Tue,?11?Oct?2022?16:44:13?+0200?writes:

?Davis?Vaughan?writes:

????>>>?I've?got?a?bit?more?information?about?this?one.?It?seems?like?it
????>>>?(only??not?sure)?appears?when?`TZ?=?"UTC"`,?which?is?why?I?didn't?see
????>>>?it?before?on?my?Mac,?which?defaults?to?`TZ?=?""`.?I?think?this?is?at
????>>>?least?explainable?by?the?fact?that?those?"optional"?fields?aren't
????>>>?technically?needed?when?the?time?zone?is?UTC.

????>>?Exactly.??Debugging?`[<-.POSIlt`?with

????>>?x?<-?as.POSIXlt(as.POSIXct("2013-01-31",?tz?=?"America/Chicago"))
????>>?Sys.setenv(TZ?=?"UTC")
????>>?x[1]?<-?NA

????>>?shows?we?get?into

????>>?value?<-?unclass(as.POSIXlt(value))
????>>?if?(ici)?{
????>>?for?(n?in?names(x))?names(x[[n]])?<-?nms
????>>?}
????>>?for?(n?in?names(x))?x[[n]][i]?<-?value[[n]]

????>>?where

????>>?Browse[2]>?names(value)
????>>?[1]?"sec"???"min"???"hour"??"mday"??"mon"???"year"??"wday"??"yday"??"isdst"
????>>?Browse[2]>?names(x)
????>>?[1]?"sec"????"min"????"hour"???"mday"???"mon"????"year"???"wday"???"yday"
????>>?[9]?"isdst"??"zone"???"gmtoff"

????>>?Without?having?looked?at?the?code,?the?docs?say

????>>??zone??(Optional.)?The?abbreviation?for?the?time?zone?in?force?at
????>>?that?time:??""??if?unknown?(but??""??might?also?be?used?for
????>>?UTC).

????>>??gmtoff??(Optional.)?The?offset?in?seconds?from?GMT:?positive
????>>?values?are?East?of?the?meridian.??Usually??NA??if?unknown,
????>>?but??0??could?mean?unknown.

????>>?so?perhaps?we?should?fill?with?the?values?for?the?unknown?case?

????>>?-k

????>?Well,

????>?I?think?you?both?know??I'm?in?the?midst?of?dealing?with?these
????>?issues,?to?fix?both

????>?[.POSIXlt??and
????>?[<-.POSIXlt

????>?Yes,?one?needs?a?way?to?not?only?"fill"?the?partially?filled
????>?entries?but?also?to?*normalize*?out-of-range?values
????>?(say?negative?seconds,?minutes?>?60,?etc)

????>?All?this?is?available?in?our?C?code,?but?not?on?the?R?level,
????>?so?yesterday,?I?wrote?a?C?function?to?be?called?via?.Internal(.)
????>?from?a?new?R?that?provides?this.

????>?Provisionally?called

????>?balancePOSIXlt()

????>?because?it?both?balances?the?9?to?11?list-components?of?POSIXlt
????>?and?it?also?puts?all?numbers?of?(sec,?min,?hour,?mday,?mon)
????>?into?a?correct?range?(and?also?computes?correctl?wday?and?yday?numbers).
????>?but?I'm?happy?for?proposals?of?better?names.
????>?I?had?contemplated??validatePOSIXlt()?as?alternative,?but?then
????>?dismissed?that?as?in?some?sense?we?now?do?agree?that
????>?"imbalanced"?POSIXlt's?are?not?really?invalid?..

????>?..?and?yes,?to?Davis:??Even?though?I've?spent?so?many?hours?with
????>?POSIXlt,?POSIXct?and?Date?during?the?last?week,?I'm?still
????>?surprised?more?often?than?I?like?by?the?effects?of?timezone
????>?settings?there.

????>?Martin

I?have?committed?the?new?R?and?C?code?now,?defining??balancePOSIXlt(),
to?get?feedback?from?the?community.

I've?extended?the?documentation?in??help(DateTimeClasses),
and?notably?factored?out?the?description
of??POSIXlt??mentioning?the??"ragged"?and?"out-of-range"?cases.

This?needs?more?testing?and?experiments,?and?I?have?not
announced?it??NEWS??yet.

Planned?next?is?to?use?it?in??[.POSIXlt?and?[<-.POSIXlt
so?they?will?work?correctly.

But?please?share?your?thoughts,?propositions,?...

Martin


[snip]